Yeah it was too short an amount of time to really get to grips with the issue.
But John Lofton, (the dude harassing Zappa constantly) is just a joke. He doesn't seem to even understand the concept of free speech.
And he's playing dirty as well, always trying to get Zappa to admit to advocating incest or something by asking leading questions, "Do you support lyrics that advocate incest"... Does the guy really think Zappa supports incest or is he just trying to catch him out?! I dunno... stupid.
But yeah, I can't comment on America as have never been there, but from an outsiders point of view the influence and scale of Christianity does seem pretty scary.